Method and apparatus for maintaining the status of objects in computer networks using virtual state machines

ABSTRACT

A network appliance for monitoring, diagnosing and documenting problems among a plurality of devices and processes (objects) coupled to a computer network utilizes periodic polling and collection of object-generated trap data to monitor the status of objects on the computer network. The status of a multitude of objects is maintained in memory utilizing virtual state machines which contain a small amount of persistent data but which are modeled after one of a plurality of finite state machines. The memory further maintains dependency data related to each object which identifies parent/child relationships with other objects at the same or different layers of the OSI network protocol model. A decision engine verifies through on-demand polling that a device is down. A root cause analysis module utilizes status and dependency data to locate the highest object in the parent/child relationship tree that is affected to determine the root cause of a problem. Once a problem has been verified, a “case” is opened and notification alerts may be sent out to one or more devices. A user interface allows all objects within the network to be displayed with their respective status and their respective parent/child dependency objects in various formats.

FIELD OF THE INVENTION

This invention relates generally to computer networks and morespecifically, to an apparatus and methods for identifying, diagnosing,and documenting problems in computer networks including networkingdevices, servers, appliances, and network services collectively known asobjects.

BACKGROUND OF THE INVENTION

Much prior art has focused on identifying network and/or system faultconditions. Additionally, prior art has used topological network mapsand diagnostic tools to display network fault conditions. Such toolshave been designed to allow less skilled network administrators toconduct support from a network or system management station.Occasionally, network and/or system management systems interface with anexterior system for the documentation of problems and resolutions.Integration is often problematic requiring extensive manipulation andcorrelation of alarm conditions prior to problem and problem resolutiondocumentation.

Such a traditional approach is inefficient on several levels. Thetraditional model assumes an administrator is available to activelymonitor the network or system management station. In an environmentwhere adequately trained human resources are unavailable, anadministrator dedicated to monitoring the network management system is aluxury many technical staffs do not have. A successful system musttherefore identify a fault condition and have an established methodologyof contacting the appropriate personnel when a fault condition exists.

The current paradigm for network and system management systems is torepresent fault information via a topological map. Typically a change incolor (or other visual cue) represents a change in the condition of thenetwork or system. This method, as currently applied, is appropriatewhen a single layer of the Open Systems Interconnect (OSI) logicalhierarchical architecture model can represent the fault condition. Forexample, a fault condition associated with layer two devices can beadequately represented by a layer two topological map. However, tomaintain the current paradigm of representing fault conditiontopologically, a topology map should present a view of the networkconsistent with complex multi-layer dependencies. Topologicalrepresentations of large networks are also problematic. A large networkis either squeezed onto a single screen or the operator must zoom in andout of the network to change the view. This common approach ignoresknown relationships between up and downstream objects in favor of apercentage view of the network, e.g. 100% equals the entire network, 50%equals one-half the network.

Further, adequate documentation and description of a problem or faultconditions and its corresponding resolution is essential but difficultto achieve within the confines of a current network or system managementsystems. Typically the problem description and problem resolution aredocumented external to the network or system management system. As aresult of using an external system to document problems and theirresolution, a dichotomy is created between the machine events in thenetwork management system and the external system which records humanintervention. Furthermore, the network management system will typicallygenerate multiple events for a single object, such association oftenlost when translated to an external system. Reconciling the machine viewof the network management system with that of the external systemdocumenting the problem description/problem resolution is quite oftendifficult and unsuccessful.

Current network management tools depend upon the discovery ofnetwork/system devices associated with the network, typically throughdiscovery of devices at layer two of the OSI model. Thereafter thenetwork is actively rediscovered using the tool to maintain a currentview of the network or system.

A need exists for a technique to topologically represent complexmulti-layer relationships between managed objects including complexdependencies between objects operating at multiple layers of the OSImodel.

A need exists for a technique to discover, maintain and document thecurrent state of the network based on known network/system objects andto detect deviations from the known state of the network and report suchdiscovered deviations as faults.

SUMMARY OF THE INVENTION

The invention discloses a network management appliance and methods foridentifying, diagnosing, and documenting problems in computer networksusing the appliance. The devices and process available on a network, aswell as grouping of the same, are collectively referred to hereafter as“objects”. Accordingly, a monitored or managed object may be physicaldevice(s), process(es) or logical associations or the same. The networkappliance comprises one or more a polling modules, a decision engine, adatabase, case management module including a user interface. The networkappliance monitors objects throughout the network and communicates theirstatus and/or problems to any number of receiving devices includingworldwide web processes, e-mail processes, other computers, PSTN or IPbased telephones or pagers.

The Status Poller periodically polls one or more monitored networkobjects and receives fault responses thereto. The Trap Receiver receivesdevice generated fault messages. Both the Trap Receiver and StatusPoller generate and transmit decision requests to the decision engine.The decision engine interacts with the database and the case managementmodule to monitor the status of problems or “cases” which have beenopened. The case management module interacts with the variousnotification devices to provide the status updates and to provideresponses to queries.

The status of a monitored object is maintained in memory using a virtualstate machine. The virtual state machines are based on one or aplurality of different finite state machine models. The decision enginereceives input data, typically event messages, and updates the virtualstate machines accordingly. The inventive network appliance recordsthousands of network states and simultaneously executes thousands ofstate machines while maintaining a historical record of all states andstate machines.

According to a first aspect of the present invention, In a computersystem having a processor, memory and a network interface, an apparatusfor monitoring a plurality of device or process objects operativelycoupled to the computer system over a computer network, the apparatuscomprising (a) means for monitoring the status of the plurality ofmonitored objects over the computer network, (b) a memory for storing aplurality of different finite state machine models, each finite statemachine model comprising (i) a finite set of states, only one of thestates being active at a time and referred to as the current state, (ii)a finite set of input events that trigger state changes and execution ofactions, (iii) a finite set of transitions, each of which, given acurrent state and a specific input event, cause a transition of thefinite state machine model to a next state, and (iv) a set of actionsassociated with selected of the finite states; (c) the memory forfurther storing a virtual state machine associated with each of theplurality of monitored objects, each virtual state machine comprising(i) data identifying the monitored object, (ii) data identifying one ofthe plurality of finite state machine models, and (iii) data identifyingone of the finite states of the identified finite state machine model asa current state of the virtual state machine; and (d) a decision engine,coupled to the means for monitoring and the memory, for receiving inputevent data relating to one of the monitored objects and for accessingthe virtual state machine in memory associated with said one monitoredobject, the decision engine further configured to manipulate the dataidentifying the current state of the virtual state machine associatedwith said one monitored object and for determining which actionsassociated with the identified finite state machine model should beperformed.

According to a second aspect of the present invention, in an apparatusoperatively coupled over a computer network to a plurality of device orprocess objects, a method comprising (a) storing in a memory a pluralityof different finite state machine models, each finite state machinemodel comprising (i) a finite set of states, only one of the statesbeing active at a time and referred to as the current state, (ii) afinite set of input events that trigger state changes and execution ofactions, and (iii) a finite set of transitions, each of which, given acurrent state and a specific input event, cause a transition of thefinite state machine model to a next state, (iv) a set of actionsassociated with one of the states; (b) further storing in the memory avirtual state machine associated with each of the plurality of monitoredobjects, each virtual state machine comprising (i) data identifying themonitored object, (ii) data identifying one of the plurality of finitestate machine models, and (iii) data identifying one of the finitestates of the identified finite state machine model as a current stateof the virtual state machine; (c) monitoring the status of the pluralityof monitored objects over the computer network; (d) receiving inputevent data relating to one of the monitored objects; (e) accessing thevirtual state machine in memory associated with said one monitoredobject; (f) manipulating the data identifying a current state of thevirtual state machine associated with said one monitored object; and (g)executing the actions associated with the identified finite statemachine model.

According to a third aspect of the present invention, a memory forstoring data to be processed by a data processing system including anapparatus for monitoring a plurality of device or process objectsoperatively coupled to a data processing system over a computer network,the memory comprising a data structure stored in the memory and usableto maintain a virtual finite state machine associated with one of themonitored objects, the data structure comprising (a) data identifyingsaid one monitored object; (b) data identifying one of a plurality ofdifferent finite state machine models, each finite state machine modelcomprising (i) a finite set of states, only one of the states beingactive at a time and referred to as a current state, (ii) a finite setof input events that trigger state changes and execution of actions,(iii) a finite set of transitions, each of which, given a current stateand a specific input event, cause a transition of the finite statemachine model to a next state, and (iv) a set of actions associated withselected of the finite states; (c) data identifying one of the finitestates of the identified finite state machine model as a current stateof the virtual state machine.

According to a fourth aspect of the present invention, in a computersystem having a processor, memory and a network interface, an apparatusfor monitoring a plurality of device or process objects operativelycoupled to the computer system over a computer network, the apparatuscomprising (a) a poller for sending queries to the plurality ofmonitored objects and for receiving responses therefrom; (b) a trapreceiver for receiving traps generated by the monitored objects; (c) adecision engine responsive to decision requests from any of the trapreceiver and poller, the decision engine further configured to send averification query to one of the plurality of monitored objectsidentified in the decision request and for a receiving response to theverification query; (d) a memory for storing a plurality of differentfinite state machine models, each finite state machine model comprisingfinite set of states, only one of the states being active at a time andreferred to as the current state; (e) the memory further storing avirtual state machine for each of the monitored objects, each virtualstate machine comprising: (i) data identifying the monitored object,(ii) data identifying one of the plurality of finite state machinemodels, and (iii) data identifying one of the finite states of theidentified finite state machine model as a current state of the virtualstate machine; and (f) a case management module for receiving requestsfrom the decision engine to open a case related to a monitored object.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings in which:

FIG. 1 is a block diagram of a prior art computer system suitable foruse with the present invention;

FIG. 2 is a conceptual illustration of a network environment in whichthe present invention may be utilized;

FIG. 3 illustrates conceptually the internal components of the networkappliance and external elements within the network environment inaccordance with the present invention;

FIG. 4 is a conceptual block diagram of the network management applianceof the present invention illustrating the implementation of theperformance monitoring component;

FIG. 5 is a conceptual block diagram of the network management applianceof the present invention illustrating the implementation of the faultmonitoring component;

FIG. 6 is a conceptual block diagram illustrating the communicationpaths between the fault monitoring component of the inventive applianceand the external elements within the network environment;

FIG. 7 is a conceptual block diagram of the decision engine component ofthe network management appliance of the present invention;

FIG. 8 is a conceptual block diagram of the case management systemcomponent of the network management appliance of the present invention;

FIG. 9 is a conceptual block diagram of the notification enginecomponent of the network management appliance of the present invention;

FIG. 10 is a conceptual block diagram illustrating the communicationpaths between the performance monitoring component of the inventiveappliance and the external elements within the network environment;

FIG. 11 is a conceptual block diagram of a decision engine and thevarious component modules therein in accordance with the presentinvention;

FIGS. 12A-C are conceptual illustrations of a state machine andhypothetical states in accordance with the present invention;

FIG. 13 illustrates a user interface diagram identifying a targetmonitored network device and monitored parent and child devices withinthe network environment in accordance with the present invention;

FIG. 14 illustrates a user interface diagram identifying a targetmonitored network device and monitored parent and child devices withinthe network environment in accordance with the present invention;

FIG. 15 illustrates a user interface status map including a microview ofthe network and a macroview of a selected portion of the network, inaccordance with the present invention;

FIGS. 16-20 are conceptual illustrations of a state machine models andtheir respective states in accordance with the present invention;

FIG. 21 illustrates a user interface status table in accordance with thepresent invention; and

FIG. 22 illustrates a user interface status map including the dependencyrelationships of a target object and various status parameters for eachobject shown with multiple iconic representations.

DETAILED DESCRIPTION

FIG. 1 illustrates the system architecture for a computer system 100,such as a Dell Dimension 8200, commercially available from DellComputer, Dallas Tex., on which the invention can be implemented. Theexemplary computer system of FIG. 1 is for descriptive purposes only.Although the description below may refer to terms commonly used indescribing particular computer systems, the description and conceptsequally apply to other systems, including systems having architecturesdissimilar to FIG. 1.

The computer system 100 includes a central processing unit (CPU) 105,which may include a conventional microprocessor, a random access memory(RAM) 110 for temporary storage of information, and a read only memory(ROM) 115 for permanent storage of information. A memory controller 120is provided for controlling system RAM 110. A bus controller 125 isprovided for controlling bus 130, and an interrupt controller 135 isused for receiving and processing various interrupt signals from theother system components. Mass storage may be provided by diskette 142,CD ROM 147 or hard drive 152. Data and software may be exchanged withcomputer system 100 via removable media such as diskette 142 and CD ROM147. Diskette 142 is insertable into diskette drive 141 which is, inturn, connected to bus 130 by a controller 140. Similarly, CD ROM 147 isinsertable into CD ROM drive 146 which is connected to bus 130 bycontroller 145. Hard disk 152 is part of a fixed disk drive 151 which isconnected to bus 130 by controller 150.

User input to computer system 100 may be provided by a number ofdevices. For example, a keyboard 156 and mouse 157 are connected to bus130 by controller 155. An audio transducer 196, which may act as both amicrophone and a speaker, is connected to bus 130 by audio controller197, as illustrated. It will be obvious to those reasonably skilled inthe art that other input devices such as a pen and/or tablet and amicrophone for voice input may be connected to computer system 100through bus 130 and an appropriate controller/software. DMA controller160 is provided for performing direct memory access to system RAM 110. Avisual display is generated by video controller 165 which controls videodisplay 170. Computer system 100 also includes a network adapter 190which allows the system to be interconnected to a local area network(LAN) or a wide area network (WAN), schematically illustrated by bus 191and network 195.

Computer system 100-102 are generally controlled and coordinated byoperating system software. The operating system controls allocation ofsystem resources and performs tasks such as process scheduling, memorymanagement, and networking and I/O services, among other things. Inparticular, an operating system resident in system memory and running onCPU 105 coordinates the operation of the other elements of computersystem 100. The present invention may be implemented with any number ofcommercially available operating systems including UNIX, Windows NT,Windows 2000, Windows XP, Linux, Solaris, etc. One or more applications220 such as the inventive network management application may executeunder control of the operating system 210. If operating system 210 is atrue multitasking operating system, multiple applications may executesimultaneously.

In the illustrative embodiment, the present invention may be implementedusing object-oriented technology and an operating system which supportsexecution of object-oriented programs. For example, the inventive systemmay be implemented using a combination of languages such as C, C++,Perl, PHP, Java, HTML, etc., as well as other object-oriented standards.

In the illustrative embodiment, the elements of the system areimplemented in the C++ programming language using object-orientedprogramming techniques. C++ is a compiled language, that is, programsare written in a human-readable script and this script is then providedto another program called a compiler which generates a machine-readablenumeric code that can be loaded into, and directly executed by, acomputer. As described below, the C++ language has certaincharacteristics which allow a software developer to easily use programswritten by others while still providing a great deal of control over thereuse of programs to prevent their destruction or improper use. The C++language is well-known and many articles and texts are available whichdescribe the language in detail. In addition, C++ compilers arecommercially available from several vendors including BorlandInternational, Inc. and Microsoft Corporation. Accordingly, for reasonsof clarity, the details of the C++ language and the operation of the C++compiler will not be discussed further in detail herein. The programcode used to implement the present invention may also be written inscripting languages such as Perl, Java Scripts, or non-compiled PHP. Ifrequired, the non-compiled PHP can be converted to machine readableformat.

Network Communication Environment

FIG. 2 illustrates a telecommunications environment in which theinvention may be practiced such environment being for exemplary purposesonly and not to be considered limiting. Network 200 of FIG. 2illustrates a hybrid telecommunication environment including both atraditional public switched telephone network as well as packet-switcheddata network, such as the Internet and Intranet networks and apparatusbridging between the two. The elements illustrated in FIG. 2 are tofacilitate an understanding of the invention. Not every elementillustrated in FIG. 2 or described herein is necessary for theimplementation or the operation of the invention.

Specifically, a packet-switched data network 202 comprises a networkappliance 300, a plurality of processes 302-306, plurality of monitoreddevices 314 a-n, external databases 310 a-n, external services 312represented by their respective TCP port, and a global network topology220, illustrated conceptually as a cloud. One or more of the elementscoupled to global network topology 220 may be connected directly througha dedicated connection, such as a T1, T2, or T3 connection or through anInternet Service Provider (ISP), such as America On Line, MicrosoftNetwork, Compuserve, etc.

A gateway 225 connects packet-switched data network 202 to circuitswitched communications network 204 which includes a central office 210and one or more traditional telephone terminating apparatus 308 a-n.Circuit switched communications network 204 may also include, althoughnot shown, a traditional PSTN toll network with all of the physicalelements including PBXs, routers, trunk lines, fiber optic cables, othercentral offices etc. Terminating apparatus 308 a-n may be implementedwith either a digital or analog telephone or any other apparatus capableof receiving a call such as modems, facsimile machines, cellulartelephones, etc., such apparatus being referred to collectivelyhereinafter as a terminating apparatus, whether the network actuallyterminates. Further, the PSTN network may be implemented as either anintegrated services digital network (ISDN) or a plain old telephoneservice (POTS) network.

Each network consists of infrastructure including devices, systems,services and applications. Manageable network components utilizemanagement mechanisms that follow either standard or proprietaryprotocols. Appliance 300 supports multiple interfaces to manageabledevices from various points within its architecture, providing theflexibility to monitor both types of network components.

Components that can be managed using standard or public protocols(including items such as routers, switches, servers, applications,wireless devices, IP telephony processes, etc.) are designed under thepremise that such components would reside in networks where a networkmanagement system is deployed. Such devices typically contain a MIB(Management Information Base), which is a database of network managementinformation that is used and maintained by a common network managementprotocol such as SNMP (Simple Network Management Protocol). The value ofa MIB object can be retrieved using SNMP commands from the networkmanagement system. Appliance 300 monitors the raw status events fromsuch infrastructure directly using various standard protocol queriesthrough a Status Poller 330 and a Trap Receiver 332, as explainedhereinafter.

Network components that were not designed with network managementapplications may have internal diagnostics capabilities that make itpossible to generate an alarm or other data log. This data may beavailable via an interface and/or format that is proprietary in nature.Such systems may also have the ability to generate log files in textformat, and make them available through supported interfaces such ase-mail. If event processing capability is needed, appliance 300 canmonitor such network components through custom status plug-ins modules.

Network Appliance Overview

In the illustrative embodiment, except for specific interface hardware,network appliance 300, referred to hereafter as simply as “appliance300”, may be implemented as part of an all software application whichexecutes on a computer architecture similar to that described withreference to FIG. 1. As illustrated in FIGS. 3-5, appliance 300 cancommunicate either directly or remotely with any number of devices, orprocesses, including the a worldwide web processes 302, a PersonalDigital Assistant 304, an e-mail reader process 306, a telephone 308,e.g., either a traditional PSTN telephone or an IP-enabled telephonyprocess 311, and/or a pager apparatus 310. In addition, appliance 300can communicate either directly or remotely with any number of externalmanagement applications 312 and monitored devices 314. Suchcommunications may occur utilizing the network environment illustratedin FIG. 2 or other respective communication channels as required by thereceiving or process.

Appliance 300 monitors network objects, locates the source of problems,and facilitates diagnostics and repair of network infrastructure acrossthe core, edge and access portions of the network. In the illustrativeembodiment, appliance 300 comprises a status monitoring module 318, aperformance monitoring module 316, a decision engine 324, a casemanagement module 326 and database 348. The implementations of thesemodules as well as their interaction with each other and with externaldevices is described hereafter in greater detail.

The present invention uses a priori knowledge of devices to be managed.For example, a list of objects to be monitored may be obtained fromDomain Name Server. The desired objects are imported into the appliance300. The relationships between imported objects may be entered manuallyor detected via an existing automated process application. In accordancewith the paradigm of the invention, any deviation from the importednetwork configuration is considered a fault condition requiring amodification of the source data. In this manner the network managementappliance 300 remains in synchronization with the source data used toestablish the network configuration.

Status Monitoring Module

A Status Monitoring Module 318 comprises a collection of processes thatperform the activities required to dynamically maintain the networkservice level, including the ability to quickly identify problems andareas of service degradation. Specifically, Status Monitoring Module 318comprises Status Poller Module 330, On-Demand Status Poller 335, StatusPlug-Ins 391, Bulk Plug-In Poller 392, Bulk UDP Poller 394, Bulk ifOperStatus Poller 396, Bulk TCP Poller 398, Bulk ICMP Poller 397, TrapReceiver 332, Status View Maintenance Module 385, and Status Maps andTables Module 387.

Polling and trapping are the two primary methods used by appliance 300to acquire data about a network's status and health. Polling is the actof asking questions of the monitored objects, i.e., systems, servicesand applications, and receiving an answer to those questions. Theresponse may include a normal status indication, a warning thatindicates the possibility of a problem existing or about to occur, or acritical indication that elements of the network are down and notaccessible. The context of the response determines whether furtherappliance 300 action is necessary. Trapping is the act of listening fora message (or trap) sent by the monitored object to appliance 300. Thesetrap messages contain information regarding the object, its health, andthe reason for the trap being sent.

A plurality of plug-ins and pollers provide the comprehensive interfacefor appliance 300 to query managed objects in a network infrastructure.Such queries result in appliance 300 obtaining raw status data from eachnetwork object, which is the first step to determining network statusand health. The various plug-ins and pollers operate in parallel,providing a continuous and effective network monitoring mechanism.Pollers may utilize common protocols such as ICMP (Ping), SNMP Get,Telnet, SMTP, FTP, DNS, POP3, HTTP, HTTPS, NNTP, etc. As a network growsin size and complexity, the intelligent application of polling andtrapping significantly enhances system scalability and the accuracy ofnot only event detection, but also event suppression in situations wherecase generation is not warranted.

Status Poller

Fault detection capability in appliance 300 is performed by StatusPoller 330 and various poller modules, working to effectively monitorthe status of a network. Status Poller 330 controls the activities ofthe various plug-ins and pollers in obtaining status information frommanaged devices, systems, and applications on the network. FIG. 6illustrates the status flow between network appliance 300 and externalnetwork elements. Status Poller 330 periodically polls one or moremonitored devices 314A-N. Status Poller 330 generates a fault poll queryto a monitor device 314 and receives, in return, a fault poll response.The fault poll queries may be in the form of any of a ICMP Echo, SNMPGet, TCP Connect or UDP Query. The fault poll response may be in theform of any of a ICMP Echo Reply, SNMP Response, TCP Ack or UDPResponse. Status Poller 330 may also receive a fault data request in URLform from web process 302. In response, Status Poller 330 generates andtransmits fault data in HTML format to web process 302. Status Poller330 generates decision requests for decision engine 334 in the form ofmessages. In addition, Status Poller 332 receives external data from anexternal management application 312. Trap Receiver 332 receives devicegenerated fault messages from monitored devices 314. Both Trap Receiver332 and Status poller 330 generate decision requests for decision engine334 in the form of messages.

Status Poller 330 determines the needed poll types, segregates managedobjects accordingly, and batch polls objects where possible. A Scheduler373 triggers the Status Poller 330 to request polling at routineintervals. During each polling cycle, each monitored object is polledonce. If any objects test critical, all remaining normal objects areimmediately polled again. A Dependency Checker module which is part ofthe Root Cause Analysis Module determines which objects have changedstatus from the last time the Status Poller 330 was run, and determines,using the current state objects and the parent/child relation data,which objects are “dependency down” based on their reliance on anupstream object that has failed. This process repeats until there are nonew critical tests found. Once the polling cycle is stable, a “snapshot”of the network is saved as the status of the network until the nextpolling cycle is complete. The network status information obtained iswritten into database 352 for use by other processes, such as theDecision Engine 334 when further analysis is required.

Polling a network for status information is an effective method of datagathering and provides a very accurate picture of the network at theprecise time of the poll, however, it can only show the state of thenetwork for that moment of time. Network health is not static. Amonitored object can develop problems just after is has been polled andreflected a positive operational result. Moreover, this changed statuswill not be known until the device is queried during the next pollingcycle. For this reason appliance 300 also incorporates the use of theTrap Receiver 332 to provide near real-time network status details.

Trap Receiver

A trap is a message sent by an SNMP agent to appliance 300 to indicatethe occurrence of a significant event. An event may be a definedcondition, such as a link failure, device or application failure, powerfailure, or a threshold that has been reached. Trapping provides a majorincremental benefit over the use of polling alone to monitor a network.The data is not subject to an extended polling cycle and is as real-timeas possible. Traps provide information on only the object that sent thetrap, and do not provide a complete view of network health. Appliance300 receives the trap message via Trap Receiver 332 immediatelyfollowing the event occurrence. Trap Receiver 332 sends the details toStatus View Maintenance Module 385, which requests the Status Poller 330to query the network to validate the event and locate the root cause ofthe problem. Confirmed problems are passed to Case Management Module 326to alert network management personnel.

The On-Demand Status Poller 335 provides status information to DecisionEngine 334 during the verification stage. Unlike the Status Poller 330,On-Demand Status Poller 335 only polls the objects requested by theDecision Engine 334. Since this is usually a small subset of objects,the status can typically be found more quickly. The responses from thesepolls are fed back to the Decision Engine 334 for further processing andvalidation.

The Status View Maintenance Module 385 provides a gateway functionbetween the Status Poller 330, and Root Cause Analysis and the DecisionEngine Modules. The Status View Maintenance Module 385 controls themethod by which network status information is created, maintained, andused. It serves as the primary interface for the depiction of networkstatus details in the Status Maps and Status Table 387. Detailed objectstatus information is presented through four (4) statuses: raw,dependency, decision, and case.

The Status Maps and Tables Module 387 is used to generaterepresentations of complex relationships between network devices,systems, services and applications. Status Maps and Tables Module 387works in conjunction with web server application 381 using knowntechniques and the HTML language to provide a web accessible userinterface to the data contained in database 352. A Status Map depict theprecise view of managed objects and processes as defined during theimplementation process. The Status Map provides a fast and concisepicture of current network issues, providing the ability to determinethe specific source of network failure, blockage or other interference.Users can zoom to the relevant network view, and launch anobject-specific Tools View that assists in the diagnostics andtroubleshooting process and may include links to third party managementtools, such as Cisco Resource Manager Essentials (RME), etc.

A Status Table enables a tabular view of managed network infrastructure.All managed network components 314 can be displayed individually, orassembled under categories according to device type, location, or theirrelationship to the monitoring of Groups of objects representingcomplete processes or other logical associations. As described in theUser Interface section hereafter, a series of unique status iconsclearly depict the operational state of each object, with the option toinclude more comprehensive status views including greater details on thevarious process elements for managed objects.

Status Plug-Ins/Bulk Pollers

As will be understood by those skilled in the arts, a plug-in, as usedherein, is a file containing data used to alter, enhance, or extend theoperation of an parent application program. Plug-ins facilitateflexibility, scalability, and modularity by taking the input from the aproprietary product and interfacing it with the intended applicationprogram. Plug-in modules typically interface with Application ProgramInterfaces (API) in an existing program and prevent an applicationpublisher from having to build different versions of a program orinclude numerous interface modules in the program. In the presentinvention plug-ins are used to interface the status poller 335 withmonitored objects 314.

The operation of plug-ins and bulk pollers is conducted at routineintervals by the Status Poller Module 330, and, on an as-needed basis,by the request of the On-Demand Status Poller Module 335. In theillustrative embodiment, the primary status plug-ins and pollers includeStatus Plug-Ins 391, Bulk Plug-In Poller 392, Bulk UDP Poller 394, Bulkif OperStatus Poller 396, Bulk TCP Poller 398 and Bulk ICMP Poller 397.

Status Plug-Ins 391 conduct specific, individual object tests. BulkPlug-In Poller 392 makes it possible to conduct multiple simultaneoustests of plug-in objects. Unlike many network management systems thatrely solely on individual object tests, the Bulk Plug-In Poller 392enables a level of monitoring efficiency that allows appliance 300 toeffectively scale to address larger network environments, includingmonitoring via SNMP (Simple Network Management Protocol). Used almostexclusively in TCP/IP networks, SNMP provides a means to monitor andcontrol network devices, and to manage configurations, statisticscollection, performance, and security.

Bulk UDP Poller 394 is optimized to poll for events relating to UDP(User Datagram Protocol) ports only. UDP is the connectionless transportlayer protocol in the TCP/IP protocol stack. UDP is a simple protocolthat exchanges datagrams without acknowledgments or guaranteed delivery,requiring that error processing and retransmission be handled by otherprotocols. Bulk UDP Poller 394 permits multiple UDP polls to be launchedwithin the managed network.

Bulk if OperStatus Poller 396 monitors network infrastructure for theoperational status of interfaces. Such status provides information thatindicates whether a managed interface is operational or non-operational.

Bulk TCP Poller 398 polls for events relating to TCP (TransmissionControl Protocol) ports only. Part of the TCP/IP protocol stack, thisconnection-oriented transport layer protocol provides for full-duplexdata transmission. Bulk TCP Poller 398 permits multiple TCP polls to belaunched within the managed network.

Bulk ICMP Poller 397 performs several ICMP (ping) tests in parallel.Bulk ICMP Poller 397 can initiate several hundred tests without waitingfor any current tests to complete. Tests consists of an ICMPecho-request packet to an address. When an ICMP echo-reply returns, theraw0 status is deemed normal. Any other response or no answer within aset time generates a new echo-request. If an ICMP echo-reply is notreceived after a set number of attempts, the raw status is deemedcritical. The time between requests (per packet and per address), themaximum number of requests per address, and the amount of time to waitfor a reply are tunable by the network administrator using appliance300.

Performance Monitoring Module

The primary component of performance monitoring module 316 isperformance poller 322. Performance poller 322 is the main device bywhich appliance 300 interacts with monitored device(s) 314 a-n and isresponsible for periodically monitoring such devices and reportingperformance statistics thereon. Performance poller 322 is operativelycoupled to application(s) 312, monitored device(s) 314, decision engine334 and web process(es) 302. FIG. 10 illustrates the communication flowbetween the performance poller 322 and decision engine 334, as well asexternal elements. Performance poller 322 polls monitored device(s) 314a-n periodically for performance statistics. Specifically, performancepoller 322 queries each device 314 with an SNMP Get call in accordancewith the SNMP standard. In response, the monitored device 314 provides aperformance poll response to performance poller 322 in the form of anSNMP Response call, also in accordance with the SNMP standard. Based onthe results of the performance poll response, performance poller 322generates and transmits decision requests to decision engine 334 in theform of messages. Such decision requests may be generated when i) aspecific performance condition occurs, ii) if no response is receivedwithin predefined threshold, or iii) if other criteria are satisfied.Decision engine 334 is described in greater detail hereinafter. Inaddition, one or more external management applications 312 provideexternal management data to performance poller 322 in the form ofmessages.

In the illustrative embodiment, performance poller 322 may have anobject-oriented implementation. Performance poller 322 receives externaldata from applications 312 through message methods. Such externalapplications may include Firewalls, Intrusion Detection Systems (IDS),Vulnerability Assessment tools, etc. Poller 322 receives performancedata requests from web process 302 via Uniform Resource Locator (URL)methods. In response, poller 322 generates performance data for webprocess 302 in the form of an HTML method. In addition, poller 322receives performance poll response data from a monitored device 314 inthe form of an SNMP response method. In addition, poller 322 receivesperformance poll response data from a monitored device 314 in the formof an SNMP response method. As output, poller 322 generates aperformance poll query to a monitored device 314 in the form of an SNMPGet method. Performance poller 322 generates decision requests todecision engine 334, in the form of a message.

Performance Poller 322 obtains performance data from network devices andapplications, creating a comprehensive database of historicalinformation from which performance graphs are generated through the userinterface of appliance 300, as described hereafter. Such graphicsprovide network management personnel with a tool to proactively monitorand analyze the performance and utilization trends of various devicesand applications throughout the network. In addition, the graphs can beused for diagnostics and troubleshooting purposes when network issues dooccur.

A series of device-specific Performance Plug-ins 321 serve as theinterface between the Performance Poller 322 and managed networkobjects. The performance criteria monitored for each component beginswith a best practices of network management approach. This approachdefines what elements within a given device or application will bemonitored to provide for the best appraisal of performance status. Themanaged elements for each device or application type are flexible,allowing for the creation of a management environment that reflects thesignificance and criticality of key infrastructure. For instance, shouldthere be an emphasis to more closely monitor the network backbone or keybusiness applications such as Microsoft® Exchange, a greater focus canbe placed on management of this infrastructure by increasing theperformance criteria that is monitored. Likewise, less criticalinfrastructure can be effectively monitored using a smaller subset ofkey performance criteria, while not increasing the management complexitycaused by showing numerous graphs that are not needed.

Once the performance management criterion is established, thePerformance Plug-Ins are configured for each managed device andapplication. Performance elements monitored may include, but are notlimited to, such attributes as CPU utilization, bandwidth, hard diskspace, memory utilization, or temperature. Appliance 300 continuouslyqueries managed or monitored objects 314 at configured intervals oftime, and the information received is stored as numeric values indatabase.

Event Processing

The appliance 300 architecture comprises sophisticated event processingcapability that provides for intelligent analysis of raw network eventdata. Instead of accumulating simple status detail and reporting allnetwork devices that are impacted, appliance 300 attempts to establishthe precise cause of a network problem delivering the type and level ofdetail that network management personnel require to quickly identify andcorrect network issues. The primary components of event processingcapability in appliance 300 are the Root Cause Analysis Module 383 andthe Decision Engine 334.

Root Cause Analysis

When a change in network status is observed that may indicate an outageor other issue, the Status Poller 330 presents the to the Root CauseAnalysis module 383 for further evaluation. During the course of anetwork problem or outage, this may consist of tens or even hundreds ofstatus change event messages. These numerous events may be the result ofa single or perhaps a few problems within the network.

The Root Cause Analysis Module 383 works directly with the DecisionEngine 334 during the event evaluation process. Appliance 300 firstvalidates the existence of an event and then identifies the root causeresponsible for that event. This process entails an evaluation of theparent/child relationships of the monitored object within the network.The parent/child relationships are established during the implementationprocess of appliance 300, where discovery and other means are used toidentify the managed network topology. A parent object is a device orservice that must be functional for a child device or service tofunction. A child object is a device or service that has a dependency ona parent device or service to be functional. Within a networkenvironment a child object can have multiple parent objects, and aparent object can have multiple children objects. In addition, theparent and child objects to a node or monitored object may be located atthe same or different layers of the OSI network protocol model acrossthe computer network. Because of this, a Dependency Checker functionwithin Root Cause Analysis Module 383 performs a logical test on everyobject associated with a monitored object in question to isolate thesource of the problem. When appliance 300 locates the highest object inthe parent/child relationship tree that is affected by the event it hasfound the root cause of the problem.

Case Management System

The Case Management system 336 is an integral component of appliance 300and provides service management functionality. Whereas the DecisionEngine 334 works behind the scenes to identify and validate faults, CaseManagement system 336 is the interface and tool used to manageinformation associated with the state of the network. Case Managementsystem 336 provides a process tool for managing and delegating workflowas it relates to network problems and activities. The Case Managementgenerates service cases (or trouble tickets) for presentation anddelivery to network management personnel.

Case management system 336 comprises a CMS application module 350, adatabase 352, a notification engine 356 and an escalation engine 354, asillustrated. CMS application module 350 comprises one or moreapplications and perform the CMS functionality, as explainedhereinafter. CMS applications 350 receive CMS requests, in the form ofURL identifiers from decision engine 334. In response, CMS applications350 generate and transmit notification requests to notification engine356, in the form of messages. CMS applications 350 generate and transmitCMS data to a worldwide web process 302 in the form of HTML data.Database 352 receives CMS queries from CMS applications 350 in the formof messages and generates in response thereto a CMS response in the formof a message, as well. In addition, database 352 receives notificationqueries from notification client 364, in the form of messages andgenerates, in response there, notification responses to notificationclient 364 in the form of messages as well.

Case Management system 336 accommodates Auto cases and Manual cases.Cases passed to the Case Management System from the Decision EngineModule appear as AutoCases. These system-generated cases are associatedwith a network problem. Appliance 300 has determined that the nodereferenced in the case is a device responsible for a network problem,based on the findings of Root Cause Analysis and the Decision Engine334. The Auto Case is automatically assigned an initial priority levelthat serves until the case is reviewed and the priority is modified toreflect the significance of the problem relative to the network impactand other existing cases being handled.

Cases entered into Case Management system 336 by the network manager ornetwork management personnel are called Manual Cases. This supports thegeneration, distribution, and tracking of network work orders, or canaid in efforts such as project management. Using a web browser,personnel can obtain the case data from either on-site or remotelocations, and access a set of device-specific tools for diagnostics andtroubleshooting. Unlike other general-purpose trouble ticketing systems,the appliance 300 has case management capabilities are specificallyoptimized and oriented to the requirements of network managementpersonnel. This is reinforced in both the types and level of informationpresented, as well as the case flow process that reflects the specificpath to network issue resolution. Opening a case that has been generatedshows the comprehensive status detail such as the impacted network node,priority, case status, description, and related case history. Thenetwork manager or other personnel can evaluate the case and take theaction that is appropriate. This may include assigning the case to anetwork engineer for follow-up, or deleting the case if a device hasreturned to fully operational status.

The main Case Management screen of the user interface provides a portalthrough web server application 381 from which all current case activitycan be viewed, including critical cases, current priority status, andall historical cases associated to the specific object. Case data isretained in appliance 300 to serve as a valuable knowledge-base of pastactivity and the corrective actions taken. This database is searchableby several parameters, including the ability to access all cases thathave pertained to a particular device. A complete set of options isavailable to amend or supplement a case including: changing casepriority; setting the case status; assigning or re-assigning the case tospecific personnel; correlating the case to a specific vendor case orsupport tracking number, and updating or adding information to providefurther direction on actions to be taken or to supplement the casehistory.

Escalation engine 354 tracks escalations and requests notifications asneeded. Escalation engine 354 generates and transmits escalation queriesto database 352 in the form of messages and receives, in responsethereto, escalation responses in the forms of messages. In addition,escalation engine 354 generates and transmits notification requests, inthe form of messages, to notification server 360 of notification engine356, in the form of messages. Automated policy-based and roles-basedcase escalation processes ensure that case escalations are initiatedaccording to defined rules and parameters. Cases not responded to withinpre-established time periods automatically follow the escalation processto alert management and other networking personnel of the open issue.

Notification Engine

When a new auto case or manual case is generated or updated, appliance300 initiates a notification process to alert applicable networkpersonnel of the new case. This function is provided throughNotification Engine 356. Appliance 300 utilizes a configurablenotification methodology that can map closely an organization's specificneeds and requirements. Appliance 300 incorporates rules- andpolicy-based case notification by individual, role, or Group, andincludes additional customizability based on notification type andcalendar. Supported notification mechanisms include various terminaltypes supporting the receipt of standard protocol text messaging ore-mail, including personal computer, text pager, wireless PersonalDigital Assistant (PDA), and mobile phones with messaging capability.The e-mail or text message may contain the important details regardingthe case, per the notification content format established in systemconfiguration.

As illustrated in FIG. 9, notification engine 356 comprises notificationserver 360, database 352, notification client 364, paging client 366,paging server 367, Interactive Voice Response (IVR) server 368 and SMTPmail module 369. Notification engine 356 generates notifications viae-mail and pager as necessary. Notification server 360 acceptsnotification requests, determines notification methods, and storesnotifications in database 352. As stated previously, notification server360 receives notification requests from CMS applications 350.Notification server generates and transmits Point Of Contact (POC)queries in the form of messages to database 352 and receives, inresponse thereto, POC responses, also in the form of messages.Notification client 364 generates notifications using appropriatemethods. Notification client 364 generates and transmits notificationqueries, in the form of messages, to database 352 and receives inresponse thereto notification responses, also in the form of messages.In addition, notification client 364 generates and transmits pagerequests in the form of messages to paging client 366. Notificationclient 364 further generates, in the form of messages, IVR requests toIVR server 368 and e-mail messages to SMTP mail module 369. Pagingclient 366 receives page requests from notification client 364 andforwards the page requests onto page server 367. Paging server 367generates pager notifications, in the form of messages, to a pagerdevice 310. Paging server 367 accesses a TAP terminal via a modem oruses the Internet to forward the pager notification. IVR server 368receives IVR requests and calls phone 308 via an IVR notification in theform of a telephone call which may be either packet-switched orcircuit-switched, depending on the nature of the terminating apparatusand the intervening network architecture. SMTP mail module 369 processesnotifications via e-mail and acts as a transport for pagingnotifications. SMTP mail module 369 generates messages in the form ofe-mail notifications to e-mail process 306 and PDA notifications topersonal digital assistant device 304.

Decision Engine

Decision Engine 334 is an extensible and scaleable system formaintaining programmable Finite State Machines created within theapplication's structure. Decision Engine 334 is the portion of systemarchitecture that maintains the intelligence necessary to receive eventsfrom various supporting modules, for the purpose of verifying,validating and filtering event data. Decision Engine 334 is thecomponent responsible for reporting only actual confirmed events, whilesuppressing events that cannot be validated following the comprehensiveanalysis process.

Referring to FIG. 7, decision engine 334 comprises, in the illustrativeembodiment, a queue manager 340, decision processor 344, case generator346, database 352 and one or more plug in modules 342. As illustrated,decision engine 334 receives decision requests from any of Performancepoller 322, Status Poller 330 or Trap Receiver 332, in the form ofmessages. A queue manager 340 manages the incoming decision requests ina queue structure and forwards the requests to decision processor 344 inthe form of messages. Decision processor 344 verifies the validity ofany alarms and thresholds and forwards a generation request to casegenerator request 346 in the form of a message. Case generator 346, inturn, compiles cases for verification and database information andgenerates a CMS request which is forwarded to case management system336, described in greater detail hereinafter.

In addition, decision processor 344 generates and transmits devicequeries in the form of messages to database 352. In response, database352 generates a device response in the form of message back to decisionprocessor 344. Similarly, decision processor 344 generates and transmitsverification queries in the form of messages to plug in module 342. Inresponse, module 342 generates a verification response in the form of amessage back to decision processor 344. Plug in module 342 generates andtransmits verification queries in the form of messages to a monitoreddevice 314. In response, monitored device 314 generates a verificationresponse in the form of a message back to plug-in module 342.

Decision engine 334 may be implemented in the C programming language forthe Linux operating system, or with other languages and/or operatingsystems. Decision engine 334 primarily functions to accept messages,check for problem(s) identified in the message, and attempts to correctthe problem. If the problem cannot be corrected the decision engine 334opens a “case”. In the illustrative embodiment, decision engine 334 maybe implemented as a state-machine created within a database structurethat accepts messages generated by events such as traps and changesstate with messages. If the decision engine reaches certain states, itopens a case. The main process within the decision engine state-machinepolls a message queue and performs the state transitions and associatedtasks with the transitions. Events in the form of decision requests areprocessed by the decision engine/virtual state-machine. The decisionmodule/virtual state-machine processes the request and initiates averification query. The verification response to the verification queryis processed by the decision module/virtual state-machine. Based on theconfiguration of the decision module/state-machine the decisionmodule/state machine initiates a case management module case request.Events are polls, traps, and threshold violations generated by thestatus poller, fault trapper, and performance poller respectively.

As shown in FIG. 11, decision engine 334 comprises several continuouslyrunning processes or modules including populate module 380, commandmodule 382, decision module 384, variable module 386, on demand statuspoller module 388, and timer module 390, described in greater detailhereinafter. These processes may launch new processes when required. Inthe illustrative embodiment, these processes share database tables indatabase 352 as a means for communication by accessing and manipulatingthe values within the database. In FIGS. 4-6 and 10, the functions ofDecision Engine 334 are performed by command module 382, decision module384, variable module 386, on demand status poller module 388, and timermodule 390, described in greater detail hereinafter. In FIG. 7, thefunctions of Decision Processor 344 are performed by decision module384, variable module 386, on demand status poller module 388, and timermodule 390. The functions of Case Generator 346 is performed by commandmodule 382.

Populate Module

The populate module 380 creates and initializes the state machine(s) tothe “ground” state for each managed object 314 whenever a user commitschanges to their list of managed objects. In the illustrativeembodiment, unless purposefully overridden, the populate module 380 willnot overwrite the current machine state for a managed object. Otherwise,notifications could be missed. Also, the deletion of an object upon acommit results in the deletion of all state machines, timers, andvariables associated with the object to prevent unused records andclutter in database 352.

Command Module

The command module 382 retrieves records from the command table,performs the task defined in a database record, and, based on the resultreturned by the command, places a message in the message queue, i.e. theMessage Table. In the illustrative embodiment, a command can be anyexecutable program, script or utility that can be run using the system() library function.

In illustrative embodiment, the command module 382 may be implemented inthe C programming language as a function of a Decision Engine object andperform the functions described in the pseudo code algorithm set forthbelow in which any characters following the “#” symbol on the same lineare comments:

-   -   while TRUE # loop forever    -   retrieve the record that has been sitting in the commands_queue        table for the longest period of time    -   use the system command (or some other as yet to be determined        method) to execute the command found in the action field of the        current record. The argument list for action will be build using        the values found in the host, poll, instance, and argument        fields of the current record. Upon completion of the command, if        the message found in the message field is not blank, put the        message into the message queue.    -   #end loop forever

Decision Module

The decision module 384 retrieves messages from the message queue,determines which state machine the message is intended for, changes thestate of the machine based on the content of the message, and “farmsout” to the other modules the tasks associated with the state change. Inthe illustrative embodiment, a task has associated therewith a number ofoptional components including a type, action, arguments, condition andoutput message. A brief description of each task component is shownbelow:

-   -   type—identifies which module, i.e., command, variable, timer, or        on demand state poller, that is to perform the task. The action        of some types of tasks may be handled by the decision module and        not sent to another module. For example, a message with the type        “say” is just a request to put a new message into the message        queue. The decision module handles such task.    -   action—the specific action the module is to take. For example,        increment a counter or start a timer.    -   arguments—any arguments required to complete the action    -   condition—if present, identifies a condition that must be met        before the associated message can be put into the message queue.        A condition may consist of a comparison between the value of a        variable stored in the variables table and a constant value or        the value of another variable that evaluates as either true or        false. An example condition would be “count>5”, which means that        the value of the value field in the variables table record where        the value of the varName field is ‘count’ for the current object        should be greater than five for a message to be put into the        queue. Condition expressions may be of the form: <VAR_NAME        COMPARISON_OPERATOR VALUE>[[AND|OR] [VAR_NAME        COMPARISON_OPERATOR VALUE]] . . . By adhering to this format,        the code that parses the condition expression will not have to        be changed if the condition expression changes. Also, such        format allows for arbitrarily complex condition expressions.    -   output message—the message to be put into the message queue upon        completion of the task. The output message can be blank        indicating that there is no message to put into the message        queue on completion of the task. Since messages are deleted as        they are taken or “popped” from the message queue, the messages        may be logged to the log table in database 352 to provide a        permanent record of message traffic.

In order to provide additional flexibility to the arguments field of theactive_timers, command_queue, and variable_queue tables, the argumentsfield in the transition_functions and state_functions tables may beallowed to contain patterns that can match any of the field names foundin the messages table or the value of any varName field in the variablestable. When a matching pattern is found it is replaced with the valuefrom the messages table field that the pattern matches or, if thepattern matches a varName field in the variables table, the pattern isreplaced with the appropriate value from the from the value field in thevariables tables. The format for a replaceable pattern may be:

%[PATTERN]%

Where PATTERN is count, name, or saveInfo, for example. Pattern matchingand replacement may be done within the decision module before a “task”record is created for one of the queues. The varName field in thevariables table should not have a value that conflicts with the fieldnames in the messages table. Since the message table is checked first,the use of a varName that matches a field in the messages table wouldresult in the pattern being replaced with a value different from whatthe user expected. To prevent this from happening, any attempt to add arecord to the variable table may have to have the value of the varNamefield checked against a list or reserved words.

In illustrative embodiment, the decision module 384 may be implementedin the C programming language as a function of a Decision Engine objectand perform the functions described in the pseudo code algorithm setforth below in which any characters following the “#” symbol on the sameline are comments:

1 while True # run forever retrieve all messages from the messages table(with a LIMIT of 100 messages) 2  for each message  parse the messagerecord into its component parts: message, object  (host, poll,instance), and extra_info  using the object value create an SQL querythat will retrieve the  current state record for all active machines ofthe object 3   for each machine of object   use the message and thecurrent state of the machine to create an   SQL query that will retrievethe next state of the machine 4    if a next state is found    updatethe current state record for the machine in the    current_state tableto the new state    Using the current machine type, the current state(pre-    transition) and the message, create an SQL query that will   retrieve all tasks that are to be performed as a result of the   machine receiving the current message from the   transition_functions table 5     for each task     determine the typeof task (timer, counter, status     request, or command) and insert intothe appropriate     module's queue a task record with field values setto     the values found in the current transition_functions     tablerecord. If the arg field from the     transition_functions recordcontains a recognized     replaceable string with the pattern%[PATTERN%],     replace the string with the value retrieved from the    current messages table record from the field that     matches thereplaceable string. If the pattern does not     match one of the fieldnames from the messages     table, Check the variables table for arecord with a     varName field with a value that matches the pattern.If     a record is found, replace the pattern with the value of     thevalue field     from the variables table record with the matching    varName     # end for each task     Using the current machine typeand the post transition     state create an SQL query that will retrieveall tasks     that are to be performed as a result of the machine    “arriving” at the next state from the state_functions     table. Ifthe arg field from the state_functions record     contains a recognizedreplaceable string, replace the     string with the value retrieved fromthe current record     from the field that matches the replaceablestring. 6      for each task      determine the type of task (timer,counter,      status request, or command) and insert into      theappropriate module's queue a task record      with field values set tothe values found in the      current transition_functions table record.If the      arg field from the transition_functions record      containsa recognized replaceable string with      the pattern %[PATTERN%],replace the string      with the value retrieved from the current     messages table record from the field that      matches thereplaceable string. If the pattern      does not match one of the fieldnames from the      messages table, Check the variables table for      arecord with a varName field with a value that      matches the pattern.If a record is found,      replace the pattern with the value of thevalue      field from the variables table record with the      matchingvarName      # end for each task 4    # end if 3   # end for eachmachine of object 2  # end for each message 1 # end of while foreverloopVariable Module

The Variable module 386 retrieves records from the variable_queue table,performs the task defined in the record, and, upon completion of thetask, puts the associated message into the message queue. Currentlydefined tasks include incrementing a counter, decrementing a counter,setting a counter to a specific value, and saving a “note” for lateruse. All tasks performed by the variable module 386 consist of eithersetting a variable to a value or updating a variable with anew value. Inthe illustrative embodiment, task statements may be assignmentstatements of the form:VAR_NAME=VALUE

Where VAR_NAME is the name of variable being set or updated and VALUE isthe value that VAR_NAME is being set to. VALUE can be of any data type(integer, float, or string, e.g.). VALUE can be a single value, such as6, or consist of an expression that can include the VAR_NAME, such ascount+1. If present in the current variable record, a condition has tobe met before the message is put into the message queue.

In illustrative embodiment, the variable module 386 may be implementedin the C programming language as a function of a Decision Engine objectand perform the functions described in the pseudo code algorithm setforth below in which any characters following the “#” symbol on the sameline are comments:

1 while TRUE # loop forever  retrieve all records ordered by time in anascending order from the  variable queue with a LIMIT of 100 records 2  for each record   if the the value of the action field is a non-emptystring    determine the name of the variable that is to be set orupdated.    The name of the variable will always be the Ivalue of theas-    signment statement and be of the form %[VAR_NAME]% =   [SOME_VALUE] where VAR_NAME is replaced with the    actual variablename (count, e.g.). Using the VAR_NAME    create an SQL query that willdetermine whether or not a    record for this variable exists in thevariables table   if the variable is not in the variables table,   INSERT a record into the variables table with the varName set    toVAR_NAME and value set to SOME_VALUE   if the variable is in thevariables table,    UPDATE the record with varName set to VAR_NAME and   value set to SOME_VALUE 3     if there is a non-null value in thecondition field of     the current record      create an SQL query usingthe condition value (“count >      5″, e.g.) that will test whether orexpression defined in      the condition is true or false     performthe query 4      if the query returns “true” (i.e., the condition hasbeen      met)       insert the message found in the message field      of the current record into the message queue.      # end if 3    # end if     else there is no condition. insert the message found inthe     message field of the current record into the message queue    else there is no condition. insert the message found in the    message field of the current record into the message queue 2   # endfor each record 1 # end loop forever

On Demand Status Poller Module

The on demand status poller module 388 retrieves records from thestatus_request table with a user defined frequency, e.g. every 10seconds. The module improves efficiency by batching status requestswhich will all be “launched” at the same time. The retrieved statusrequests are “farmed out” to the appropriate poller module. The ondemand status poller module 388 waits for the results of the statusrequests to be returned by the pollers. Based on the result, theappropriate message is inserted into the message queue.

In illustrative embodiment, the on demand status poller module 388 maybe implemented in the C programming language as a function of theDecision Engine object and perform the functions described in the pseudocode algorithm set forth below, in which any characters following the“#” symbol on the same line are programmers comments:

retrieve all records from the statReq table

-   -   Based on the type of the poll request (ICMP, TCP, PLGN, etc)        “farm out” t he status requests to the appropriate bulk poller.

retrieve the results (up or down) returned by the bulk pollers

-   -   for each status poll result    -   insert the appropriate message into the message queue

# end for loop

Timer Module

The timer module 390 retrieves records from the active_timers table,performs the tasks defined in the record, and, upon completion of thetask, puts the associated message into the message queue. Currentlydefined tasks include expiring a timer and clearing a timer. If presentin the current timer record, a condition has to be met before themessage is put into the message queue. An example condition would be“UNIX_TIMESTAMP>exp_time”, which checks to see if a timer has expired.

In illustrative embodiment, the timer module 390 may be implemented inthe C programming language as a function of the Decision Engine objectand perform the functions described in the pseudo code algorithm setforth below in which any characters following the “#” symbol on the sameline are programmers comments:

1 while TRUE # loop forever retrieve all records with an action ofeither clearTimer, clearTimers, or resetTimer 2  for each record  if theaction is clearTimer  if the current record has a non-blank argument,delete the  oldest record with an action of setTimer and with a message that equals the value of the argument field for the current object/machine tuple. Otherwise, delete the oldest record  with anaction of setTimer for the current object/machine  tuple without regardfor the value of the message field  else if the action is clearTimersdelete all records with an  action of setTimer for the currentobject/machine tuple  else if the action is resetTimer reset theappropriate timer by  updating the timer record that is to be reset withthe following  psuedoSQL statement: update timer_que set timer_id = current time, argument = current_argument where object =  currentobject and message = current message.  # end for each record  delete allrecords with an action of either clearTimer or  clearTimers  retrieveall records where the action is setTimer and  timer_id < current timewith a LIMIT of 100 records 3   for each record 4    if there is anon-null value in the condition field    of the current record    createan SQL query using the condition value    perform the query 5     if thequery returns “true” (i.e., the     condition has been met) insert the    message found in the message field of     the current record intothe message     queue. 5     # end if the condition is met 4    # end ifthere is a condition    else there is no condition. insert the message   found in the message field of the current record    into the messagequeue. 3   # end for each record   delete all of the records justretrieved. Delete the   records based on the unique timer_id to ensurethat   the correct records are deleted. 1 # end loop forever

One or more of the above described processes or modules, includingpopulate module 380, command module 382, decision module 384, variablemodule 386, on demand status poller module 388, and timer module 390,operate in conjunction to collectively perform the functions theelements of decision engine 334 and other elements of appliance 300 asnoted herein.

Finite and Virtual State Machines

FIGS. 12A-C are provided as visual aid to help the reader understand thenature of state machines. A two-state state machine can be representedby the diagram illustrated in FIG. 12A. The diagram FIG. 12A can beinterpreted as follows:

If you are at StateA and if you get a message “message”, then do what isspecified in “transition” and after that we are at StateB.

Such For design purposes, the same state machine can be represented asillustrated in FIG. 12B. A more complex machine may be illustrated inthe diagram of FIG. 12C.

The state machine illustrated in the diagram of FIG. 12C may berepresented as a virtual state machine in database 352 as shown in Table1 below:

TABLE 1 “sm_Table” state_name Function Message Target_state Active AFuncA( ) Msg_1 B 1 B FuncB( ) Msg_2 A 0

In the illustrative embodiment, messages are the mechanism to make astate machine change state, in addition to control messages toinitialize state machines or to forcefully change state. Messages arrivefrom a message queue. At any time only the active states can acceptmessages. The last column in Table 1 determines the active state for thestate machine. Only one state is active (active=1) and all other statesare inactive (active=0). If no active state can accept the message, themessage is discarded. Initially, the state machine is at ground state,meaning the ground state is the only active state. After handling of themessage, the machine returns to the ground state again.

Messages are kept in a database table and handled in a first come firstserved basis. Each message has an associated timestamp with it, whichhelps to determine which message arrived earlier. Since that timestampis unique it is also used as the message id, as shown in Table 2 below:

TABLE 2 “messages” msg_id msg 971456805855844 TCP_down 971456805878973SNMP_down

A state machine will frequently request waiting before changing states.Instead of launching new processes for each wait request, a single timerprocess operating on a set of timers may do the same job with much lessresource. A special timers table is employed for that purpose. Since aunique id for each timer is needed, a timestamp may also be used forthat purpose, as shown in Table 3 below:

TABLE 3 “timers” Timer_id expiration msg 971456805855844 971456865855844Wait1min_over 971456805858344 971457105855844 Wait5min_overThe timer process operates on the timers table by checking for theexpiration of timers and if the current time is past expiration, deletesthe entry from table and inserts the message into the message queue.

Frequently the functions to be executed at state transitions are statusrequests. Instead of launching those requests everytime they arerequested, the requests may be kept in a status_request table, as shownin Table 4 below. The status handler process handles the execution ofthose status requests using Table 4.

TABLE 4 “status_request” Req_id StatusReqst_name msg 971456805858344Check_TCP TCP_OK 971457105855844 Check_AC AC_OK

Given a fundamental understanding of state machines and how theirrespective states can be changed using message input, the finite statemachine models on which all the virtual state machines used within theappliance 300 are is described hereafter. Records contained withindatabase 352 define several finite state machine models managed bydecision engine 334.

Finite State Machines

Decision Engine 334 is designed to minimize resource utilization, allowfor the launching of multiple Finite State Machines, and conductmultiple activities simultaneously. Decision Engine 334 can be used toperform any decision making process which can be modeled by a FiniteState Machine. A finite state machine model in accordance with theillustrative embodiment may be defined by the following:

-   -   A finite set of states. Each state represents a condition or        step in the decision process. Only one state in each machine may        be active at a time, and this is referred to as the ‘Current        State’    -   A finite set of inputs. (events that trigger state changes and        the execution of actions) Inputs are represented as messages        pertaining to objects, providing the events that trigger state        changes and the execution of actions. Any message that does not        have a Current State with a transition waiting (listening) for        it will be considered invalid and discarded. This provides the        validation process for the Decision Engine 334. An infinite        number of possible messages are filtered to allow only a finite        number of messages through when they are valid.    -   Finite set of transitions. Given a particular state and a        particular message, transfer is facilitated to the next state.        At the point in time when the transition occurs, it can initiate        any tasks defined for the transition and target state. Each        transition is uniquely defined by the ‘Current State, Message        and Destination State’.    -   Set of transition tasks that define zero or more actions that        are to be performed based on the current state and input        received (e.g., anytime current state is ‘StateA’ and the input        ‘MessageA’, perform the transition tasks for ‘StateA, MessageA.’        For example, actions may include launching the On-Demand Status        Poller Module to recheck the status of an object, setting a        timer, and opening a case that identifies an object as being        critical.    -   Set of state tasks that define zero or more actions that are to        be performed based on the next state independent of the input or        current state (e.g., anytime the target state is ‘StateA’        perform the state tasks for ‘StateA’).

To keep the number of records in database 352 manageable no matter howlarge the number objects managed by apparatus 300, each type of finitestate machine is defined only once. For each managed object 314 avirtual state machine comprising the name of the object, the type ofstate machine and the current state of the state machine is added to andmaintained by database 352. As events are received, the decision engine334 uses database 352 to “look up” the next state and the actions to beperformed in the tables and records that define the state machines.FIGS. 16-20 illustrate several finite state machine models supported bythe illustrative embodiment of the apparatus 300 including the finiteset of states within each finite state machine model and the input datanecessary to change states. A description of each finite state machinemodel is described below.

noWaitVerify State Machine

FIG. 16 illustrates the noWaitVerify finite state machine model 1600supported by the illustrative embodiment of appliance 300. The purposeof the noWaitVerify state machine 1600 is to verify the status of anobject (as up or down) by requesting that the appropriate poller modulerecheck the status of the object. If the result of the recheck matchesthe last status of the object, the object's status is verified and acase is opened or updated as appropriate. The functionality of thenoWaitVerify state machine is described in pseudo code forth below:

Accept critical “status events” from the dependency module.

Send a poll request to the on-demand status poller.

If the “status” is verified to be critical, update a case with“warning”.

If the “status” remains critical for 10 minutes, update a case with“critical”.

If the “status” remains critical for 1 hour, update case.

If the “status” returns to normal, verify status and update a case with“normal”.

Table 5 below identifies the next state transitions and associatedactions for the noWaitVerify state machine:

State Name Input Next State Actions Ground Critical verifyCritical Start10 min. Timer Start 1 hr. Timer Re-poll status of object verifyCriticalCritical critical Start 500 sec. Timer Open new case verifyCriticalNormal Ground No actions critical Critical600 critical Update case with10 min. warning critical Critical3600 critical Update case with 1 hourwarning critical Normal verifyNormal Re-poll status of object criticalRetest critical Start 500 sec. Timer Re-poll status of objectverifyNormal Critical critical Clear current 500 sec. Timer Start a new500 sec. timer verifyNormal Normal Ground Update case with “returned tonormal” message

icmpVerify State Machine

FIG. 17 illustrates the icmpVerify finite state machine model 1700supported by the illustrative embodiment of the apparatus 300. Thepurpose of the icmpVerify state machine is to verify the status of anobject (as up or down) by requesting that the appropriate poller recheckthe status of the object. If the result of the recheck matches the laststatus of the object, the object's status is verified and a case isopened or updated as appropriate. What differentiates the nowaitVerifystate machine from the icmpVerify state machine is that the icmpVerifystate machine waits 40 seconds before requesting that an object's statusbe rechecked. The functionality of the icmpVerify state machine isdescribed in pseudo code forth below:

Accept critical “status events” from the dependency module.

Wait at least 40 seconds in case spanning tree is causing the problem.

Send a poll request to the on-demand status poller.

If the “status” is verified to be critical, open or update a case with“warning”.

If the “status” remains critical for 10 minutes, update a case with“critical”.

If the “status” remains critical for 1 hour, update case.

If the “status” returns to normal, verify status and update a case with“normal”.

slidingWindow State Machine

FIG. 18 illustrates the slidingWindow finite state machine model 1800supported by the illustrative embodiment of the apparatus 300. Thepurpose of the slidingWindow state machine is to suppress case updatesand the associated notifications caused by objects that are “flapping”.That is, objects that have a status that is repeatedly changing back andforth from up and down. The functionality of the slidingWindow statemachine is described in pseudo code forth below:

-   -   Accept “extra_info” from other state machines and update cases.    -   If the rate of AutoCase updates exceeds 5 in a sliding 30 minute        window, suppress any more, update case saying “AutoCase updates        Suppressed!”    -   If any new AutoCases come in during the suppressed state, hold        onto the latest info.    -   When the rate drops below 4 per 30 minutes, update case with the        last “info” and say “AutoCase updates Resumed!”.

upsOnline State Machine

FIG. 19 illustrates the upsOnline finite state machine model 1900supported by the illustrative embodiment of the apparatus 300. Thepurpose of the upsOnline state machine is to monitor the status of anuninterruptible power supply (UPS). The upsOnline State machine works inconcert with the upsBattery state machine. The functionality of theupsOnline state machine is described in pseudo code forth below:

Accept critical “status events” from the dependency module.

Wait for up to 5 minutes to see if power will return or update case.

When power returns wait 10 minutes to make sure it is stable.

If the “status” remains critical for 10 minutes, update a case with“critical”.

If the “status” remains critical for 1 hour, update case.

upsBattery State Machine

FIG. 20 illustrates the upsBattery finite state machine model 2000supported by the illustrative embodiment of the apparatus 300. Thepurpose of the upsBattery state machine is to monitor the battery chargelevel of a UPS. The upsBattery state machine works in concert with theupsOnline state machine. The functionality of the upsBattery statemachine is described in pseudo code forth below:

-   -   Uses object: “name:PLGN:upsBattery”    -   Same as noWaitVerifyStateMachine, accepts, when OnBattery (from        UPS OnLine State Machine), ignore any problems with the battery.    -   However, when the power is restored, let the UPS OnLine State        Machine know when the battery is OK (charged).    -   Note: Destatus(n) represents ‘comand (updateDEstatus.pl n),, “”,        “” where (n) is the status index.

In addition to the upsBattery and upsOnline state machines, theremaining state machines aren't device specific. Accordingly, regardlessif the device is a router, a switch, a personal computer, etc., theicmpVerify, icmpVerify, and slidingWindow state machines can be used.The inventive network appliance 300 reduces false positives through useof the state machines. When a device is first reported down, appliance300 doesn't alert the end user that the device is down without confirmedverification. This process is done by waiting a certain amount of timeand repolling the device. If the second poll shows that the device isstill down, appliance 300 sends out an alert. This process of verifyingstatuses before reporting alarms is facilitated by the Decision Engine334 and the state machines associated with the monitored device.

Decision Engine 334 uses the specially designed finite state machines toverify that monitored objects identified as critical by the StatusPoller Module and Dependency Checker are in fact down. Decision Engine334 then performs such functions as: Initiating detailed information insupport of new case generation for the down object, or status updates toexisting cases at specific time intervals for impacted objects,including device- or condition-specific messages that are provided bythe state machine; updating existing cases when objects becomeavailable; and suppressing case updates for monitored objects that haveexceeded a defined number of updates within a prescribed period of time.

As will be obvious to those reasonably skilled in the arts. Other statemachine models may be accommodated by appliance 300 and used similarlywithout significant reconfiguring of the device beyond recompiling ofthe appropriate code segments. Extensibility is accomplished by allowingnew and enhanced finite state machine models to be quickly developed andintroduced without the need to change system code. For example, if a newFinite State Machine is needed because a new type of status poll hasbeen created to better monitor or manage a specific object, thedefinition of this new State Machine does not require a change to theappliance 300 application software. Once the new State Machine is addedto the system, any managed object that is of the new status poll typewill be handled by the Decision Engine without requiring recompilationof any part of the underlying Decision Engine code. In addition, thefunctionality of the Decision Engine can be extended by its ability torun any program, script or utility that exists on the appliance 300application. This function can be applied to instances such as when aprocess managed by appliance 300 is identified as “down”, the FiniteState Machine for that object can be designed to run a command that willattempt to restart the process without human intervention.

The virtual state machines provide a significant scaling advantage ascompared to traditional state machines. Implementation of virtual statemachines within a database solves several constraints includingconstraints associated with memory resident state machines implementedin RAM. With the memory constraint removed, the number of virtual statemachines maintained concurrently may be increased by orders ofmagnitude. In addition, implementation of virtual machines in memoryrather that as executing processes, allows the state data of monitoredobjects to be retained through a loss of power by the network appliance.

Decision Process

In terms of decision process, the Decision Engine 334 receives potentialissues and supporting details following Root Cause Analysis. The definedFinite State Machine(s) for the identified objects are invoked tosupplement the discovery and validation process. Based on itsinstructions, the Decision Engine 334 then seeks to validate the statusof the device as well as other surrounding devices through the On-DemandStatus Poller Module 335. The On-Demand Status Poller 335 returns statusdetails to the Decision Engine 334 where the results are evaluatedfurther. Once a network issue has been isolated and validated, thesource of the problem and other supporting detail is passed to the CaseManagement system 336, which is the primary component of appliance 300'sService Management capability. Additionally, the status details relatingto the root cause and devices affected through dependency are providedto the Status View Maintenance Module 385, which depicts the status inthe Network Status Table and Status Maps 387. The various appliance 300modules continue this course of action and provide updates to both casesand status indications as status conditions change.

The Status Poller polls managed objects and awaits a response withinsystem defined parameters. Should a response not be received, the eventis forwarded to the decision engine for further analysis. Concurrently,the Trap Receiver system fault trapper will collect and forward trapinformation to the decision engine for further analysis. The output ofthe decision engine is a validated problem requiring action oracknowledgement by a human operator. The decision engine uniquelyidentifies the problem for documentation. At a minimum the uniqueness ofthe problem is established by identifying the managed object effectedand providing a date and time stamped description of the validatedproblem. The validated problem may be enhanced by further identifyingthe decision engine as the initiator of the problem, identifying thestatus of the problem, and assigning a priority to the problem. Anycombination of fields within the database may be used to develop a listof problems and the order in which the problems should be addressed. Forexample, the database may be configured to sort and list problems bypriority and date/time stamp. Thus the human technician may view a listof problems with priority one problems, sorted by age, at the top of thelist. The human operator typically will document all actions taken.Actions taken will be date/time stamp and chronologically listed withinthe problem description along with all machine-generated information.Thus the documentation/notification engine will have recorded machinegenerated validated problems along with human actions within a selfcontained, chronological description of the problem and all actionsthrough resolution. The inventive appliance suppresses the generation ofadditional problems or cases by appending to existing problemspreviously identified. For example, the inventive decision engine can beconfigured to search for an unresolved problem previously opened by thedecision engine for a specific managed object. By appending informationto the existing problem the intended viewer of the problem text, i.e.the human technician, can view all machine and human generatedinformation within its chronological context. This method significantlyreduces event storms that typically inundate network management systems.Specifically, objects that continuously flap from a “known good state”to a “fault” state typically generate events associated with thetransition from “known good state” to “fault” state. The inventiveappliance will suppress such event storms by logically grouping all suchevents within one unresolved problem associated with the root causeobject.

Database Tables and Field Definitions

A central relational database 352 is employed to facilitate datapersistence and interprocess communication. Several processes or modulesmay access the same tables in the database, so the database provides amechanism for interprocess communication. Database 352 may beimplemented with any number of commercial SQL database server products,including mySQL commercially available from mySQL AB. The databaseserver can handle a large number, e.g. 50 million records, in a singledatabase table. In the illustrative embodiment, database 352 may includethe following tables: poll, messages, current_state, state_machine,active_timers, variable_queue, command_queue, variables,transition_functions, state_functions, status_request. These tables aredefined in greater detail hereinafter:

Messages Table

The message table serves as the queue for all messages used by thedecision engine. All modules can place a message in the queue, but onlythe decision module reads messages from the queue. A message can referto a specific object and the state machine for that object or, throughthe use of wildcards, multiple objects and state machines. The fieldswithin the message table, the data type of the field and default valuethereof are listed below:

msg_id bigint(20) unsigned DEFAULT ‘0’ NOT NULL, message char(255)DEFAULT ″ NOT NULL, name char(50) DEFAULT ″ NOT NULL, method char(20)DEFAULT ″ NOT NULL, instance char(20) DEFAULT ″ NOT NULL, extra_infochar(255) DEFAULT ″ NOT NULL, PRIMARY KEY (msg_id)

current_state Table

The current_state table maintains the current state of each active statemachine within the database. The fields within the current_state table,the data type of the field and default value thereof are listed below:

machine char(20) DEFAULT ″ NOT NULL, state_name char(20) DEFAULT ″ NOTNULL, name char(30) DEFAULT ″ NOT NULL, method char(20) DEFAULT ″ NOTNULL, instance char(20) DEFAULT ″ NOT NULL, KEY state_name

state_machine Table

The state_machine table contains state transition information for everytype machine in the system. There is one record for each possible statetransition for each machine type. The fields within the current_statetable, the data type of the field and default value thereof are listedbelow:

machine char(20) DEFAULT ″ NOT NULL, state_name char(20) DEFAULT ″ NOTNULL, message char(255) DEFAULT ″ NOT NULL, target char(20) DEFAULT ″NOT NULL, PRIMARY KEY (machine,state_name,message)

machine_definition Table

The machine_definition table defines the type of machine that is to becreated for a managed object based on the “method” and “instance” of theobject. The fields within the machine_definition table, the data type ofthe field and default value thereof are listed below:

machine char(20) DEFAULT ″ NOT NULL, method char(20) DEFAULT ″ NOT NULLinstance char(20) DEFAULT ″ NOT NULL, KEY (method)

active_timers Table

The active_timers table serves as a queue for all requests for some kindof action on the part of the timer module. A request can refer to aspecific object or, through the use of wildcards, multiple objects. Uponcompletion of the action and the meeting of an optional condition, amessage will be placed into the message queue. The fields within theactive_timers table, the data type of the field and default valuethereof are listed below:

timer_id bigint(20) unsigned DEFAULT ‘0’ NOT NULL, name char(30) DEFAULT″ NOT NULL, method char(10) DEFAULT ″ NOT NULL, instance char(20)DEFAULT ″ NOT NULL machine char(20) DEFAULT ″ NOT NULL, argumentschar(50)

variable_queue Table

The variable_queue table serves as the queue for all requests for somekind of action on the part of the variable module. A request can referto a specific object or, through the use of wildcards, multiple objects.Upon completion of the action and the meeting of an optional condition,a message will be placed into the message queue. The fields within thevariable_queue table, the data type of the field and default valuethereof are listed below:

variable_id bigint(20) unsigned DEFAULT ‘0’ NOT NULL, name char(30)DEFAULT ″ NOT NULL, method char(10) DEFAULT ″ NOT NULL, instancechar(20) DEFAULT ″ NOT NULL, machine char(20) DEFAULT ″ NOT NULL,message char(255)

command_queue Table

The command_queue serves as the queue for all requests for some kind ofaction on the part of the command module. A request can refer tospecific object. or, through the use of wildcards, multiple objects.Upon completion of the action and the meeting of an optional condition,a message will be placed in the message queue. The fields within thecommand_queue table, the data type of the field and default valuethereof are listed below:

command_id big int(20) unsigned DEFAULT ‘0’ NOT NULL, name char(30)DEFAULT ″ NOT NULL, method char(10) DEFAULT ″ NOT NULL, instancechar(20) DEFAULT ″ NOT NULL, machine char(20) DEFAULT ″ NOT NULL,

variables Table

The variables table contains the values of variables associated with aparticular object that must be saved, modified, or retrieved inconjunction with a task. Examples of variables to be saved include 1) acount of the number of case updates for each managed object. It is thejob of the variables module to increment, decrement or reset counters asit works off counter requests in the variable_queue. 2) the text of thelast suppressed auto_open request. The fields within the variablestable, the data type of the field and default value thereof are listedbelow:

name char(30) DEFAULT ″ NOT NULL, method char(10) DEFAULT ″ NOT NULL,instance char(20) DEFAULT ″ NOT NULL, machine char(20) DEFAULT ″ NOTNULL, varName char(10) DEFAULT ″ NOT NULL,

transition_functions Table

The transition_functions table contains the list of actions that are tobe performed as the result of a particular machine receiving input I (amessage) while in state S. For every machine type there is a record forevery possible machine state/input combination. The fields within thetransition_functions table, the data type of the field and default valuethereof are listed below:

machine char(20) DEFAULTs ″ NOT NULL, state_name char(20) DEFAULT ″ NOTNULL, input_message char(255) DEFAULT ″ NOT NULL, type char(20) DEFAULT″ NOT NULL, action char(20) DEFAULT ″ NOT NULL, condition char(20)DEFAULT ″ NOT NULL, arguments char(50) DEFAULT ″ NOT NULL,output_message char(255) DEFAULT ″ NOT NULL, PRIMARY KEY(machine,state_name,input_message,type,action)

state_functions Table

The state_functions table contains the list of actions that are to beperformed as the result of a particular machine “arriving” at stateregardless of the input. For every machine type there will be zero ormore records for each state. The fields within the state_functionstable, the data type of the field and default value thereof are listedbelow:

machine char(20) DEFAULT ″ NOT NULL, state_name char(20) DEFAULT ″ NOTNULL, type char(20) DEFAULT ″ NOT NULL, action char(20) DEFAULT ″ NOTNULL, condition char(20) DEFAULT ″ NOT NULL, arguments char(50) DEFAULT″ NOT NULL, output_message char(50) DEFAULT ″ NOT NULL, PRIMARY KEY(machine,state_name,input_message,type,action)

status_request Table

The status_request table serves as the queue for all requests for statuspolls to be performed by the on demand status poller module. The fieldswithin the status_request function table, the data type of the field anddefault value thereof are listed below:

request_id bigint(20) unsigned DEFAULT ‘0’ NOT NULL, name char(30)DEFAULT ″ NOT NULL, method char(10) DEFAULT ″ NOT NULL, instancechar(20) DEFAULT ″ NOT NULL, message char(255) DEFAULT ″ NOT NULL,PRIMARY KEY (request Id).

The illustrative embodiment of the invention has been described with animplementation using a database 352. It will be obvious to those skilledin the art the that the actual configuration of data storage componentsmay be left to the system designer. For example, although a singledatabase is shown, more than one database may be used, or data may bestored among a plurality of databases in distributed manner. Inaddition, the data described herein may be stored in traditional memoryusing look-up tables which contain data similar to that disclosed hereinwhile still achieving the same results.

Wildcards in Messages

Wildcard usage is limited to the name, method and instance fields of themessages, active_timers, counter_queu, and command_queue tables. In theillustrative embodiment an asterisk (*) is used as the wildcardcharacter, however, it will be obvious to those skilled in the arts thatany number of characters may be used as acceptable wildcard characters.The use of an asterisk in place of a specific value in a name, method,or instance field means that this message refers to all objects thatmatch the values in the non-wildcarded fields. For example, a messagewith the following values:

-   -   714536493, ‘moveToState(Ground)’, ‘*’, ‘TCP’, ‘*’        means that the message is intended for all currently active        state machines that exist for objects with the poll type of        “TCP”. The use of an asterisk in each of the name, method, and        instance fields of a message means that the message is intended        for all active machines.

User Interface

The appliance 300 includes a web server process 381 which generates auser interface which includes a number of menu selectable options andcan dynamically generate a visual representation of the current state ofmanaged objects and the Boolean relationships between objects atdifferent layers of the Open Systems Interconnect network protocolmodel. In the illustrative embodiment, web server process 381 may beimplemented a commercially available products such as the Apache Webserver product. The dynamically generated visual representation of amanaged object can scaled down to display the desired number of upstreamand down stream objects from the target object, as illustrated in FIGS.13-15 and 22. Data regarding a monitored object(s) can be viewed in theformat of a Status Map or a Status View, as described hereafter.

The diagrams illustrated in FIGS. 13-15 are generated dynamically uponrequest from the user. Status Table and Status Map Module 387 withinappliance 300 accesses the records within database 352 to determine theupstream and downstream devices for a selected node and theirrelationships thereto. The Module 387 queries the portion of database352 which maintains the virtual state machines for the selected node andits respective parent and child nodes. The diagram is then generatedfrom this information to accurately reflect the current configurationand status of all managed objects in the conceptual diagram.

Alternatively, a map of the entire network may be generated and storedstatically in database 352 or other memory and updated periodically. Inthis embodiment, only the selected node and its data string of managedobjects (i.e., devices on which it is dependent) will be crossreferenced with the virtual state machines prior to display.

Status Map

As shown in FIG. 15, a web-based user interface is presented includingnavigation bar 1510, Status Map 1505 and a macroview graphic 1500 of thecomputer network being monitored. FIG. 22 illustrates a Status Map 2205and a macroview graphic 2200, having substantially similar format tothose shown in FIG. 15. A Selecting on the Map link under the Statusmenu on the navigation bar 1510 opens the Status Map 1505. Status Map1505 provides a zoomed or microview physical map of the selected sectionof graphic 1500, designated with a box in graphic 1500. Status map 1505shown managed objects shown in a navigable map format. Map 1505 providesa quick and easy visual guide to ascertain the network's health. ADependency Summary, show in text form, may be provided near the top ofthe map indicating the number of objects in each possible status. Themap view may be customized by selecting one or any combination of threeoptions, including Pan/Full, Group/Dependency, and Single Status/AllStatus.

When the Status Map is opened, the top and left most section of the mapis shown. This map view is referred to as the Pan mode. Navigation toother sections of the map may be performed using the single and doublenavigation arrows icons shown on the map. The single arrow will move themap one object to the left or right, or up and down. The double arrowswill move the map one full screen either to the left or right, or up anddown.

The entire Status Map 1505 may be displayed in the browser window, byselecting the View and Re-draw option commands causing the re-draw thestatus map to show the entire network. The horizontal and verticalscroll bars can be used to navigate to other parts of the map. To returnto the Pan mode, selecting the View and Re-draw commands will cause themap to return to its default status.

By default, the Status Map opens in Dependency view, similar to StatusMap 2205 shown in FIG. 22, showing physical connections between objectsbased on parent child relationships. When viewing the parent childdependency relationships between managed objects, the parent objects aresituated to the left of child objects.

The Status Map for Groups can be viewed by checking the View check boxand selecting the Re-draw button to re-draw the Status Map showingobjects according to their Group affiliation. In Group mode, the contextof parent-child is reversed. Since a Group cannot in itself be tested,the status of the Group (parent) is derived from its members (children).Parent Groups are to the left, and child members are to the right. TheGroup map depicts the relationship of various network objects inrelation to how they are associated and configured in correlation to theGroup. This permits monitoring by groups of like devices, location orsite, or specific end-to-end processes. To return to the Dependencymode, selecting the View and Re-draw commands will cause the map toreturn to its default status.

Single Status/All Status

The Status Map (by default) shows you the Single Status view for allobjects shown. Selecting the View and Re-draw commands will display afull complement of All Status icons (raw, dependency, decision engineand case), as shown in Status Map 2205 shown in FIG. 22. To show onlythe single dependency status, selecting the View and Re-draw commandsagain will display dependency status.

Each object in the status map may be visually depicted using iconsspecifically designed to provide easy recognition and visibility. Withinthe maps, the object's name may be listed directly underneath the icon.Next to the icon, the appropriate status may be listed in text oriconically (single status by default, all status when selected).Selecting on an object icon will return the Tools View for therespective item.

Relationship Indicators

The lines that connect one object to another indicate the relationshipof an object to other objects in the network. In the illustrativeembodiment, the parent objects are shown to the left and above; childrenobjects are shown to the right and below. If groups are present in themap, appliance 300 provides information depicting the Boolean dependencyexpressions that have been formulated to determine what objects/nodeshave an effect on determining the Group's operational status. Booleandependency expression symbols, indicate that a Group has been createdand this object is contributing to the overall determination of theGroup's health and operational status. Appliance 300 allows the user todefine during set-up the various individual conditions that constitutethe status of a created Group.

A circle with an ampersand inside, similar to symbol 1512 of FIG. 15,indicates an ‘AND’ Boolean function test that is taking intoconsideration the operational status of individual nodes (i.e., Node A &Node B & Node C). If any of the nodes included in the expression isdown, then the group status will show “down.” A circle with a linethrough, similar to symbol 1514 of FIG. 15, means there is an ‘OR’Boolean function test or expression. In such case, with multiple nodesbeing included in the expression (i.e., Node A or Node B or Node C), ifall of the items are down, then the status for the group will show“down.” An “f” in a circle symbol is used to indicate complexexpressions involving a combination of ‘AND’ and ‘OR’ Functions betweenthe members (i.e., ‘[(NodeA|NodeB) & (NodeC|Node D)]’ means the Group isnormal if one of Node A ‘OR’ Node B ‘AND’ one of Node C ‘OR’ Node D isnormal). No symbol bubble indicates that the Group contains only onemember. There is no need to interpret these details as Appliance 300automatically takes this logic into account when establishing a Group'sstatus. Placing a pointing device such as a mouse pointer over any ofthese symbols on the network Status Maps will show you the specificdetails of the Boolean expression.

Network Health and Navigation Graphic

As shown in FIG. 15, in the upper-right portion of the Pan Map screen,Appliance 300 provides a small-scale version of the Status Mapreflecting the entire network, referred to as a macroview or “whole”view of the network and labeled as graphic 1500. The square indicatesthe current location of the detail that is being shown in the main or“microview” Status Map. Selecting an area of the graphic map 1500 causesthe Status Map 1505 to navigate to that portion of the network re-drawthe main map at the location selected. In the contemplated embodiment,the map may be color coded to indicate which nodes or portions of themap have status other than normal, to facilitate selection thereof. Uponselecting a portion of the full network map, the user is presented witha node level diagram 1505, as illustrated in the remaining portion ofFIG. 15. As shown, a selected node, as well as all other managed objectsin its operational chain are illustrated conceptually, along with theirstatus. As shown, the status of each managed object is indicated with asphere, the color of which may indicate the status of the manageddevice.

Tools View

By selecting on the Tool icon or the node icons in the Status Map, theTools View screen opens, revealing a 3-Gen map. FIGS. 13 and 14illustrate “3-Gen” or three generation maps which display the parent andchild devices to a selected object are presented and labeledaccordingly. In addition, the status of the state machine for theselected node is illustrated. As with the presentation of FIG. 15, thestatus of each device presented in FIGS. 13 and 14 is illustrated with asphere of changeable color. In the illustrative embodiment, green may beused to indicate a node object which is functioning properly, red may beused to indicate a node object which is non responsive or failing, othercolors may be used to indicate node objects which are only partiallyfunctioning or offline, etc. It will be obvious to those skilled in thearts that other techniques may be used to represent the status of amanaged object.

FIGS. 13 and 14 illustrate a Tools view of a map 1300 and 1400,respectively, that can navigated through by selecting the arrows next tothe objects that are related to the object in question. The optionsabove the map allow access to additional information about the objectincluding case information, status information, performance information,and the ability to review any associated logs for the object. Under theCases section, selecting the Active link will open the Case Browsescreen showing all of the active cases for that object. A completehistory of cases for the object, can be obtained by selecting the Alllink, which will open the Case Browse screen and show every case (bothactive and closed) for the object in question. Selecting the Table linkor the Map link under the Status section opens the respective statusscreen, revealing the position of the object in the network. If Table isselected, the Group heading that includes the object in question opensat the top of the screen. If Map is selected, a section of the networkStatus Map is opened with the object in question approximately centeredon the screen.

If performance graphing is provided for the object, it is directlyaccessible from the Tools View by selecting the Statistics link underthe Performance section (only displayed if applicable) to open the MRTGgraphs applicable to the object. If performance graphing is notapplicable, ‘n/a’ (not available) will be listed under the Performanceheading. Selecting the View Log link (under the Log section) will openthe View Log screen. If the object open in the Tools View has associatedlog entries (typically process availability) for the current day, theyare displayed here.

Performance polling data may be graphically depicted in various viewsrepresenting each monitored performance element over different durationsof time. Graphical displays are based on the ubiquitous Multi-RouterTraffic Grapher (MRTG). Long duration views such as one (1) year areideal tools for presentation of long term trending. Smaller durationviews (in months, days, or hours) are useful to more precisely detect orevaluate specific anomalies or performance events that have occurred.

Performance thresholds can also be established for each performanceelement being monitored. Should performance levels surpass thepre-established performance baseline, appliance 300 can systematicallyidentify and log this condition, and proceed to alert network managementpersonnel through the integrated Case Management engine 336 andNotification engine 356.

Selecting the Table link under the Status menu on the navigation bar2110 opens the Status Table 2100, as illustrated in FIG. 21. The StatusTable lists managed objects in tabular format. A Dependency Summary maybe provided above the table, indicating the number of objects in eachpossible status. Below that, each object is listed with its currentstatus indicated next to it. Data presented includes: Available Tools,Object Name, Status Indicator Symbols and Description.

Appliance 300 provides the option of viewing performance in either aSingle Status mode that reflects object operational status, or an AllStatus mode that shows a more detailed view of status and processes.When this mode is selected, there are four single status indicators usedwithin the a Status Table and Status Maps. The status icons visuallydepict the operational status or severity of a network problem as shownin Table 6 below:

Status Icon Status Description Circle Normal Object is operational andfunctioning (Green) properly. Circle Warning Indicates a potentialproblem; an object (Yellow) may be down. It is currently in the processof being pulled to determine its real status. Circle Critical Object hasbeen confirmed as down; a (Red) critical failure. Circle DependencyFailed Object may or may not be down; no (Blue) way to determine due toa parent object or link failure.

A dependency failure indicates that an object between the target objectand Appliance 300 is not operating normally, and the status of theobject in question is unknown due to its inaccessibility. By selectingthe status icon for a non-dependency down object that responds to ICMP,a trace route is run between Appliance 300 and the respective object.

The architectural components of appliance 300 application detect anetwork's status, determine the root cause of a problem, verifyoperational status, and track cases pertaining to the devices, systems,services and applications. These integrated components work together toassist network management personnel identify real problems and focustheir energy on efforts to manage the network.

The All Status mode provides a user with a more comprehensive view ofnetwork performance. A unique icon reflects specific information aboutan aspect of the appliance 300 with the color presented, therebyallowing the user to view object status as a complete process shouldthey need additional background on the events leading to the statusshown or case generation.

Table 7 below is a description of the status indicators used when AllStatus is reflected in the Status Map or Status Table. This informationcan assist in the troubleshooting and diagnostics process.

Raw Status

Such Icon Status pertains to the operation of the respective object asviewed on the Status Map or Status Table.

Status Icon Status Description Diamond Normal Status (Green) The objectis Testable objects have passed the last working within test. normalparameters. Group objects are not directly testable, however their rawstatus status is evaluated by the Boolean expression of the raw statusof the members in the group. Simple relationships can indicate that“any” or “all” of the members are “normal.” Complex relationships followthe simple Boolean rules. Typically, no action is required. However,there may be tools available for these objects that can help find cluesabout critical objects. Compare raw status color to dependency anddecision engine color. Diamond Critical Status (Red) The object is notTestable objects have failed the last working within test. Look for theroot cause to start normal parameters. the troubleshooting process.Group objects are not directly testable, however their raw status statusis evaluated by the Boolean expression of the raw status of the membersin the group. Simple relationships can indicate that “any” or “all” ofthe members are “critical.” Complex relationships follow the simpleBoolean rules.Dependency StatusStatus of objects that may have been impacted through dependencyrelationship.

Status Icon Status Description Circle Normal Status (Green) The objectis Typically, no action is required. working within normal parameters.Circle Root Cause (Red) The object is a Testable objects have failed,and there root cause. are Group objects: the no failed parents. Wait forthe decision root cause of the engine to verify the status and problemis within its open a case before starting the members. troubleshootingprocess. For group objects: Look for the root cause within its members.(Blue) Dependency Failed Parent has failed. Wait for the decision engineto verify Group objects: the the status and open a case before rootcause is not one starting the troubleshooting process. of the members.

Decision Engine Status

Status of current operation of the Decision Module as it relates toanalyzing the specific object.

Status Icon Status Description Triangle Ground State (Green) There areno active No action is required unless it is State Machines fordetermined that a Finite State this object. Machine should be running.Triangle Verified Critical (Red) State Machine is Watch for the casepriority icon to active. It is verifying see if the event has led to acase or has verified the being generated. status.

Case Priority

Status indicates the presence of active cases for the object, includingthe priority as currently assigned to the case. If active cases arepresent, the user can click on the case icon and they will be routed tothe Search Results screen where the case can be accessed.

Status Icon Status Description Square No Active Cases (Green) There areno active No action is required unless other status cases for thisobject. icons indicate that there should have been a case generated.Square Informational Case (Blue) Active Manual or AutoCase Read the caseand take action as has been set to Info applicable. priority. Square LowPriority Case (Yellow) Active Manual or AutoCase Read the case. Ifapplicable, verify that object has been set is normal and close thecase. to low priority. Square Medium Priority (Orange) Case ActiveManual or AutoCase Read the case. If applicable, work on has been set tothis if there are no high priority cases to medium priority. work on.Square High Priority Case (Red) Active Manual or AutoCase Read the case.If applicable, the case has been set to high should be worked on ASAP topriority. troubleshoot and correct the issue.Placing a pointing device cursor over a status icon in a Status Map orStatus Table generates a hint box that provides a description of thestatus as set forth in Table 8 below. The values may be any of thefollowing:

Diamond Raw Status: normal (Green) Diamond Raw Status: critical (Red)Circle Dependency: normal (Green) Circle Dependency: root cause (Red)Circle Dependency: dependency failed (Blue) Triangle Decision Engine:normal (Green) Triangle Decision Engine: critical (Red) Square CaseManagement: no active cases (Green) Square Case Management: info caseactive (Blue) Square Case Management: low priority case active (Yellow)Square Case Management: medium priority case active (Orange) Square(Red)

Referring again to FIG. 22, an All Status view 2200 of a monitoredobject 2210 includes multiple status icons 2202, 2204, 2206, and 2208,in accordance with the description herein. The other managed objectswithin the view 2200 have similar status icons.

Groups

Appliance 300 allows a collection of monitored objects to be depicted asa Group. The Group is represented as an object, and it is dependent uponits member objects to determine the Group's status. The Group is thendisplayed as a standard object icon on all relevant maps. Additionally,Group objects are represented on group status maps and tables thatdepict the relationship of member objects to the Group.

Selecting a Group object from the Group Status Maps or Status Table willcause the display of an abbreviated map, which contains the Tools Viewfor the Group object. Group members may be defined in the same manner asother object dependency strings. However, when a Group's status becomesdependency failure, an inference can be made as to the source of theproblem.

Consider the example in which a site has three Uninterrupted PowerSources (UPSs) being monitored. The power supply may be modeled as aGroup by creating a Group object, and adding ‘OR’ dependencies to allthree of the UPSs. In this way, when all three UPSs fail at the sametime, the status of the Group object will go show dependency failure,signifying a strong possibility that the entire site has lost power.

The All Status states of a Group object are:

Raw Status (Diamond Icon)

-   -   Bad/Red—Member object's raw status caused Group's dependency        expression to show “Failed” (depend down).    -   Good/Green—Member object's raw status translates to good based        on expressions established (Group's dependency expression shows        “Up”).

Dependency Status (Circle Icon)

-   -   Bad/Red—This Group's member objects are considered the “root        cause” of the failure(s) occurring.    -   Bad/Blue—This Group is dependency down, and the root cause for        failure(s) is not among the Group's members.    -   Good/Green—Member object's status is good.

Decision Engine Status (Triangle Icon)

-   -   Red—This Group is being processed by the Decision Engine (is not        in “Ground State”).    -   Green—This Group is in “Ground State” in the Decision Engine.

Case Status (Square Icon)

-   -   Red—High priority AutoCase exists for this Group.    -   Orange—Medium priority AutoCase exists for this Group.    -   Yellow—Low priority AutoCase exists for this Group.    -   Blue—Information Case exists for this Group.

The user interface described above is a web based user interface. Itwill be obvious to those skilled in the arts that other user interfaceformats, such as one compatible with the many version of the Windowsoperating system may be equivalently used with the present inventionwith the same results.

From the foregoing description and attached figures, the reader willappreciate that the present invention provides a device which is capableof monitoring the status of complex networks of devices or processes,providing information regarding the status of the network or a specificdevice through a plurality of different communication channels anddisplaying accurate visual representations of a node and its immediaterelationships in the network, in a manner which is both intuitive andefficient.

Although various exemplary embodiments of the invention have beendisclosed, it will be apparent to those skilled in the art that variouschanges and modifications can be made which will achieve some of theadvantages of the invention without departing from the spirit and scopeof the invention. It will be obvious to those reasonably skilled in theart that other components performing the same functions may be suitablysubstituted. Further, the methods of the invention may be achieved ineither all software implementations, using the appropriate processorinstructions, or in hybrid implementations which utilize a combinationof hardware logic and software logic to achieve the same results. Suchmodifications to the inventive concept are intended to be covered by thedisclosure herein and any claims deriving priority from the same.

1. In a computer system having a processor, memory and a networkinterface, an apparatus for monitoring a plurality of device or processobjects operatively coupled to the computer system over a computernetwork, the apparatus comprising: (a) means for monitoring the statusof the plurality of monitored objects over the computer network; (b)first means for storing in memory a plurality of different finite statemachine models; (c) second means for storing in memory a virtual statemachine associated with each of the plurality of monitored objects; and(d) a decision engine, coupled to the first and second means for storingin the memory, for receiving input event data relating to one of themonitored objects and for accessing the virtual state machine in memoryassociated with said one monitored object, the decision engine furtherconfigured to manipulate data identifying a current state of the virtualstate machine and for determining which actions of a plurality ofactions associated with an identified finite state machine model shouldbe performed.
 2. The apparatus of claim 1 wherein each finite statemachine model comprises a finite set of states, only one of the statesbeing active at a time and referred to as the current state.
 3. Theapparatus of claim 1 wherein each finite state machine model comprises afinite set of input events that trigger state changes and execution ofactions.
 4. The apparatus of claim 1 wherein each finite state machinemodel comprises a finite set of transitions, each of which, given acurrent state and a specific input event, cause a transition of thefinite state machine model to a next state.
 5. The apparatus of claim 1wherein each finite state machine model comprises a set of actionsassociated with selected of the finite states.
 6. The apparatus of claim5 wherein the set of actions associated with selected of the pluralityof different finite state machine module comprises actions to beperformed based on a current state of the finite state machine model anda received input data.
 7. The apparatus of claim 5 wherein the set ofactions associated with selected of the plurality of different finitestate machine models comprises actions to be performed based on a nextstate of the virtual state machine model, without regard to a currentstate of the finite state machine model and any received input data. 8.The apparatus of claim 1 wherein each virtual state machine comprisesdata identifying the monitored object.
 9. The apparatus of claim 1wherein each virtual state machine comprises data identifying one of theplurality of finite state machine models.
 10. The apparatus of claim 9wherein each virtual state machine comprises data identifying one of thefinite states of the identified finite state machine model as a currentstate of the virtual state machine.
 11. In a computer system having aprocessor, memory and a network interface, an method for monitoring aplurality of device or process objects operatively coupled to thecomputer system over a computer network, a method comprising: (a)monitoring the status of the plurality of monitored objects over thecomputer network; (b) storing in memory a plurality of different finitestate machine models; (c) storing in memory a virtual state machineassociated with each of the plurality of monitored objects; (d)receiving with a decision engine input event data relating to one of themonitored objects and accessing the virtual state machine in memoryassociated with said one monitored object; and (e) manipulating with thedecision engine the data identifying the current state of the virtualstate machine and determining which actions associated with anidentified finite state machine model should be performed.
 12. Themethod of claim 11 wherein each finite state machine model comprises afinite set of states, only one of the states being active at a time andreferred to as the current state.
 13. The method of claim 12 whereineach virtual state machine comprises data identifying one of the finitestates of the identified finite state machine model as a current stateof the virtual state machine.
 14. The method of claim 11 wherein eachfinite state machine model comprises a finite set of input events thattrigger state changes and execution of actions.
 15. The method of claim11 wherein each finite state machine model comprises a finite set oftransitions, each of which, given a current state and a specific inputevent, cause a transition of the finite state machine model to a nextstate.
 16. The method of claim 11 wherein each finite state machinemodel comprises a set of actions associated with selected of the finitestates.
 17. The method of claim 16 wherein the set of actions associatedwith selected of the plurality of different finite state machine modulecomprises actions to be performed based on a current state of the finitestate machine model and a received input data.
 18. The method of claim16 wherein the set of actions associated with selected of the pluralityof different finite state machine models comprises actions to beperformed based on a next state of a virtual state machine model,without regard to a current state of the finite state machine model andany received input data.
 19. The method of claim 11 wherein each virtualstate machine comprises data identifying the monitored object.
 20. Themethod of claim 11 wherein each virtual state machine comprises dataidentifying one of the plurality of finite state machine models.
 21. Acomputer program product for use with an computer system operativelycoupled over a computer network to a plurality of device or processobjects, the computer program product comprising a computer useablemedium having embodied therein program code comprising: (a) program codefor monitoring the status of the plurality of monitored objects over thecomputer network; (b) program code for storing in memory a plurality ofdifferent finite state machine models; (c) program code for storing inmemory a virtual state machine associated with each of the plurality ofmonitored objects; (d) program code for receiving input event datarelating to one of the monitored objects and accessing the virtual statemachine in memory associated with said one monitored object; and (e)program code for manipulating the data identifying the current state ofthe virtual state machine associated with said one monitored object anddetermining which actions associated with the identified finite statemachine model should be performed.
 22. The computer program product ofclaim 21 wherein each finite state machine model comprises a finite setof states, only one of the states being active at a time and referred toas the current state.
 23. The computer program product of claim 22wherein each virtual state machine comprises data identifying one of thefinite states of the identified finite state machine model as a currentstate of the virtual state machine.
 24. The computer program product ofclaim 21 wherein each finite state machine model comprises a finite setof input events that trigger state changes and execution of actions. 25.The computer program product of claim 21 wherein each finite statemachine model comprises a finite set of transitions, each of which,given a current state and a specific input event, cause a transition ofthe finite state machine model to a next state.
 26. The computer programproduct of claim 21 wherein each finite state machine model comprises aset of actions associated with selected of the finite states.
 27. Thecomputer program product of claim 26 wherein the set of actionsassociated with selected of the plurality of different finite statemachine module comprises actions to be performed based on a currentstate of the finite state machine model and a received input data. 28.The computer program product of claim 26 wherein the set of actionsassociated with selected of the plurality of different finite statemachine models comprises actions to be performed based on a next stateof a virtual state machine model, without regard to a current state ofthe finite state machine model and any received input data.
 29. Thecomputer program product of claim 21 wherein each virtual state machinecomprises data identifying the monitored object.
 30. The computerprogram product of claim 21 wherein each virtual state machine comprisesdata identifying one of the plurality of finite state machine models.